package com.hake.core.support.spring;

import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

/**
 * @ClassName: ContextHolderUtils
 * @Description: TODO(上下文工具类)
 * @date 2012-12-15 下午11:27:39
 * 
 */
@SuppressWarnings("unchecked")
public class SpringContextHolder implements ApplicationContextAware {

	private static ApplicationContext applicationContext;

	/**
	 * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
	 */
	public void setApplicationContext(ApplicationContext applicationContext) {
		SpringContextHolder.applicationContext = applicationContext;
	}

	/**
	 * 取得存储在静态变量中的ApplicationContext.
	 * @return
	 */
	public static ApplicationContext getApplicationContext() {
		checkApplicationContext();
		return applicationContext;
	}

	/**
	 * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
	 * @param name
	 * @return
	 */
	public static <T> T getBean(String name) {
		checkApplicationContext();
		return (T) applicationContext.getBean(name);
	}

	/**
	 * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
	 * 如果有多个Bean符合Class, 取出第一个.
	 * @param clazz
	 * @return
	 */
	public static <T> T getBean(Class<T> clazz) {
		checkApplicationContext();
		@SuppressWarnings("rawtypes")
		Map beanMaps = applicationContext.getBeansOfType(clazz);
		if (beanMaps != null && !beanMaps.isEmpty()) {
			return (T) beanMaps.values().iterator().next();
		} else {
			return null;
		}
	}

	private static void checkApplicationContext() {
		if (applicationContext == null) {
			throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder");
		}
	}

	/**
	 * SpringMvc下获取request
	 * @return
	 */
	public static HttpServletRequest getHttpRequest() {
		RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
		if (null != requestAttributes) {
			HttpServletRequest request = ((ServletRequestAttributes) requestAttributes).getRequest();
			return request;
		} else {
			return null;
		}

	}

	/**
	 * SpringMvc下获取session
	 * @return
	 */
	public static HttpSession getHttpSession() {
		if (null != getHttpRequest()) {
			return getHttpRequest().getSession();
		} else {
			return null;
		}
	}
}
